IS")/.] FALCONER MASTODON. 359 



Hippotherium. indicate a similar inference of Miocene remains being 

 mixed up with Pliocene forms in the reconstructed materials of the 

 Red Cray deposit.~H. F., Oct. 20th, 1 80 7.] 



Conclusion. — On a review of the various facts and considerations 

 discussed in the preceding pages, it seems clear that the Mammalian 

 fauna of the Fluvio-marine Crag is of a Pliocene age. The un- 

 doubted association of M. (Tetraloph.^ Arvernensis and of E. {Lox- 

 odon) meridionalis in this deposit admits of no other inference. The 

 mixed contents of the Red Crag, including mammalian remains of 

 diiferent strata from the Eocene period upwards, are inferred to have 

 been deposited in the reconstructed strata also within the Pliocene 

 period ; since M. (Tetraloph.^ Arvernensis, which occurs so abun- 

 dantly in the Red Crag, has not been met with anywhere on the 

 Continent of Europe except in deposits of a Pliocene age. The Red 

 Crag sea appears to have breached a previously established and popu- 

 lated Pliocene land, and to have buried the bones referable to various 

 epochs in the same sea-bottom. 



In the preceding remarks I have purposely excluded any reference 

 to the shell- evidence, and confined the comparison strictly to the 

 Mammalian Fauna. The Mollusca have unquestionably been wielded 

 as a most powerful exponent of geological chronology, and of the 

 successive physical changes which have taken place on the surface 

 of the earth. But it will hardly be denied that the evidence pre- 

 sented by Mammalian remains, when obtained in sufficient variety 

 and abundance, is of greater significance as a test of contempora- 

 neous formation in geology, or the reverse: — 1st, Because Mam- 

 malian genera and species are everywhere shown to be of more limited 

 duration in time than the Mollusca ; and, 2ndly, because from the 

 vastly greater complexity of their relative functions, they are much 

 more susceptible of being affected by the altered climatal conditions 

 which are necessarily involved in every great physical change, and 

 which conduce most to the extinction of species. 



The conclusions to which the comparison has led are : — 



1. That the Mastodon-remains which have been met with in the 

 "Fluvio-marine Crag" and "Red Crag" belong to a Pliocene form. 

 Mastodon {Tetralophodori) Arvernensis. 



2. That the Mammalian Fauna of the Fluvio-marine Crag bears 

 all the characters of a Pliocene age, and is identical with the Sub- 

 apennine Pliocene Fauna of Italy. 



3. That the Red and Fluvio-marine Crags, tested by their Mam- 

 malian Fauna, must be considered as beds of the same geological 

 age. 



[The sequel of this paper. Part 2, " On the species of Elephant 

 found fossil in England," with remarks upon the associated Mam- 

 malia, will be communicated at a future meeting of the Society.] 



